Industrial Use Of Corbondioxide From Mineral Carbonation A Case Study From Magnesite From Salem

ABSTRACT Magnesite is a mineral with the chemical formula MgCO3 (magnesium carbonate). Mixed crystals of iron(II) carbonate and magnesite (mixed crystals known as an kerite) possess a layered structure: mono layers of carbonate groups alternate with magnesium mono layers as well as iron (II) carbonate mono layers. Manganese, cobalt and nickel may also occur in small amounts. Our project describes two rather different options for carbon dioxide (CO2) storage: (i) the fixation of CO2 in the form of inorganic carbonates, also known as ‘mineral carbonation' or ‘mineral sequestration', and (ii) the industrial utilization of CO2 as a technical fluid or as feedstock for carbon containing chemicals .In the case of mineral carbonation, captured CO2 is reacted with metal-oxide bearing materials, thus forming the corresponding carbonates and a solid by product, silica for example. Natural silicate minerals can be used in artificial processes that mimic natural weathering phenomena, but also alkaline industrial wastes can be considered. The products of mineral carbonation are naturally occurring stable solids that would provide storage capacity on a geological time scale. Moreover, magnesium and calcium silicate deposits are sufficient to fix the CO2 that could be produced from the combustion of all fossil fuels resources. To fix a tonne of CO2 requires about 1.6 to 3.7 tonnes of rock. From a thermodynamic viewpoint, inorganic carbonates represent a lower energy state than CO2; hence the carbonation reaction is exothermic and can theoretically yield energy. However, the kinetics of natural mineral carbonation is slow; hence all currently implemented processes require energy intensive preparation of the solid reactants to achieve affordable conversion rates and/or additives that must be regenerated and recycled using external energy sources.